X-chloro-g-



United States Patent fiice 3,125,5894-CHLORO-6-(HYDROXYAMINO)-1,3-BENZENEDI- SULFONAMIDES AND INTERMEDIATEArthur H. Goldkamp, Glencoe, Ill., assignor to G. D. Searle & Co.,Chicago, Ill., 21 corp'oration of Delaware No Drawing. Filed Mar. 26,,1962, Ser. No. 182,633 2 Claims. (Cl. 260-397.7)

This invention relates to certain 6-(hydroxyamino/nitro)-1,3-benzenedisulfonamides and to intermediates and processes fortheir manufacture. More particularly, this invention provides novel,useful, and non-obvious chemical compounds of the formula SIOaNH2 OgN-with the sodium or potassium salt of benzyl mercaptan in an inertsolvent medium to give the corresponding 2,4-dibenzylthio-S-nitrobenzenewhich, in turn, is converted to the apposite2,4-dichlorosulfonyl-S-nitrobenzene by contacting with chlorine in amixture of acetic acid and acetic anhydride at temperatures of the orderof -40 degrees and then hydrolyzing. The latter intermediate affords the6-nitr o-1,3-benzenedisulfonamide SOzNHi S OrNH 1':

on heating with concentrated ammonium hydroxide. Hydrogenation of thenitrodisulfonamide, using 5% palladium-on-barium-sulfate catalyst in thepresence of oxalic acid, provides the corresponding hydroxyaminoproduct. Throughout the foregoing disclosure of preparative procedures,X retains the meaning previously assigned.

The following examples describe in detail compounds 3,125,589 PatentedMar. 17., 1 964 illustrative of the present invention and methods whichhave been devised for their manufacture. However, the invention is notto be construed as limited thereby, either in spirit or in scope, sinceit will be apparent to those skilled in the art of organic synthesisthat many modifications, both of materials and of methods, may bepracticed without departing from the purpose and intent of thisdisclosure. Throughout the examples hereinafter set forth, temperaturesare given in degrees Centigrade and relative amounts of materials inparts by weight, except as otherwise noted.

EXAMPLE 1 A; 2,4-Dibenzylthi0-1-Chl0r0-5-Nitr0benzene To a mixture of103 parts of 1,2,4-trichloro-5-nitrobenzene, parts of benzyl mercaptan,and 1000 parts of tetrahydrofuran is added, with agitation, parts ofaqueous 34% potassium hydroxide. The resultant mixture is heated at theboiling point under reflux in an atmosphere of nitrogen for 4% hours,then cooled and diluted with 3 volumes of water. The solid precipitatethrown down is filtered olf and recrystallized from a mixture of acetoneand methanol to give 2,4-dibenzylthio-1- chloro-S-nitrobenzene meltingat 124.5-127".

B. I -Chl0ro-2,4-Dichlorosulfonyl-S-Nitrobenzene A mixture of 410 partsof acetic acid and approximately 14 parts of acetic anhydride issaturated with chlorine by bubbling the gas into the mixture during 20minutes. The flow of gas is continued while 50 parts of2,4-dibenzylthio-l-chloro-S-nitrobenzene is added during 6-7 minutes,followed after 20 minutes by 100 parts of water. Heat is evolved, andthe reactants are chilled from a maximum of 40 to around 15 withvigorous agitation, at which point introduction of chlorine is stoppedand the solid precipitate which forms is filtered off. Washed with a 1:1mixture of acetic acid and petroleum ether (B.P. 60-71), and then withpetroleum ether alone, the 1- chloro-2,4-dichlorosulfonyl-S-nitrobenzenethus isolated melts at 167l69.

C. 4-Chl0r0-6-Nitr0-1,3-Benzenedisulfonamide A mixture of 41 parts of1-chloro-2,4-dichlorosulfonyl- S-nitrobenzene and 250 parts'ofconcentrated ammonium hydroxide is distilled to dryness at 85-95. Theresidue is washed by trituration with cold water, and then withmethanol, to give 4-chloro-6-hydroxyamino-1,3-benzenedisulfonamidemelting at 277282. The product has the formula EiOaNHa EXAMPLE 2 4 -Chl0r0 6-Hydr0xyamin0-1 ,3 -Benzened isulfonamid e A mixture of 48 parts of4-chloro-6-nitro-1,3-benzenedisulfonamide, 10 parts of oxalic acid, 6parts of 5% palladium-on-barium-sulfate catalyst, and 2500 parts ofethanol is maintained with vigorous agitation under approximately 2atmospheres of hydrogen until 2 molecular equivalents of the hydrogenare absorbed. The mixture 4 is then filtered, and the filtrate is freedof solvent by distil- What is claimed is: lation. The residue iscrystallized from a mixture of 1. 4-chloro-6-hydroxyamino 1,3benzenedisulfonmethanol and benzene, and then from water, to give 4- idchloro-6-hydroxyamino-l,3-benzenedisulfonamide which 2 2,4.dib 1thi -1;1 1 -5- itr ben ene, decomposes above 190. The product has the formula5 soiNHi References Cited in the file of this patent HOHN UNITED STATESPATENTS 2,965,656 Novello Dec. 20, 1960 S01NII1 10 2,986,573 Topliss etal May 30, 1961

1. 4-CHLORO-6-HYDROXYAMINO-1,3-BENZENEDISULFONAMIDE.